1. Field of the Invention
The present invention relates to a liquid crystal display device.
2. Description of the Related Art
It is known that a fluorescent tube is used as a backlight of a liquid crystal display device (see Japanese Patent Application Laid-open No. 2009-175377 (related U.S. patent application: Publication No. US2009/0190066)). The fluorescent tube serves as a light source that converts ultraviolet rays generated through electric discharges into visible light beams by irradiating phosphors with the ultraviolet rays. Specifically, electrons released by the discharge collide with mercury atoms. Then, the mercury atoms receive energy from the electrons, and thus the ultraviolet rays are generated. The ultraviolet rays generated in this manner excite the phosphors applied to a wall surface of the fluorescent tube, and thus light is emitted. In order that the fluorescent tube may emit light uniformly, it is desirable that the mercury atoms be dispersed uniformly therein.
Conventionally, in a so-called direct backlight type liquid crystal display device in which a backlight is disposed on a rear surface side of a liquid crystal display panel, the fluorescent tube is retained by holders (also referred to as pin molds) at portions other than end portions of the fluorescent tube. The holders are fixed to a frame formed of a metal. Therefore, heat of the fluorescent tube easily transfers to the frame via the holders, and hence the portions of the fluorescent tube retained by the holders easily decrease in temperature. As a result, temperature distribution may be generated in the fluorescent tube, and due to different temperatures in the temperature distribution, the dispersion of the mercury atoms may become unequal. This may interfere with uniform light emission.
The holders retain the fluorescent tube at a plurality of portions, and hence reducing the number of the holders may prevent generation of the temperature distribution. However, if the number of the holders is reduced, vibration amplitude of the fluorescent tube may increase due to influence of an impact during transportation or the like. In this situation, the fluorescent tube may be broken due to collision with other members, and therefore measures to prevent the breakage are required to be provided.